Skateboard wheels are designed in many different sizes and hardnesses. Skateboard wheels are made of a rubber-like material called urethane. The size and hardness of the wheels affect the smoothness of the ride on a skateboard, how well it handles, and its speed. Skateboard wheels are normally 52 mm to 60 mm and have their own ball bearings built in. Street skateboard wheels are usually very hard, which allows them to slow down quickly and store energy as you move along. Park wheels are usually made of a softer urethane for better bite and handling. Modern skateboard wheels are bidirectional, meaning that they can be attached in either direction unlike the wheels on a car or the back wheel of a bicycle. This means that if the edges start to wear, you can flip the wheels and use them on the other side. Skateboard wheels are attached to the trucks by hex head axle bolts and ABEC (or another company’s) ball bearings to provide the free-spinning movement of the wheels.
Trucks are axles attached to a baseplate. Most trucks are made from an aluminum alloy and they are very strong. Trucks come in many different shapes, sizes and colors. Trucks are made from cast metal and allow the skater to turn the board. Depending how tightly the nut on the kingpin is secured, the trucks can be loose or tight just like the suspension on a car. The main purpose of having trucks that are not fixed is to enable you to turn or “carve” without lifting your front wheels off the ground. The looser your trucks are, the further you will be able to lean in one direction or the other.
Wheels don’t just keep your skateboard rolling — they are also responsible for keeping you on your feet as you tackle different terrain. Wheels attach to the axles of the trucks with a hex bolt and there are 8 bearings, two inserted into each wheel with a spacer between. The wheels come in a variety of shapes, from 50 to 55 mm, and different hardnesses. Most skateboard wheels, like mentioned above, are made from urethane, and have a hardness rating stamped on the wheel (for example: 95a, or 100a – always with an “a” after the number). The higher the number, the harder the wheel. For example, a 101a wheel is harder than a 95a. So a good choice for street riding might be a 100a or 101a. A 95a would do well on ramps and in a skateboard park.
So, a skateboard is made up of three main parts: the deck, the trucks, and the wheels. The deck is the flat part on top (or mostly flat) where you plant your feet. The trucks are bolted to the bottom of the deck. This is your suspension and axles for the deck and wheels. The wheels bolt onto the ends of the trucks and include wheel bearings so the wheels can spin. Wheels come in different sizes and hardnesses to help you custom tailor your ride.
Source by Dean Novosat